If the plugin is "missing from the disk", then it looks like you didn't install it correctly. Read the installation instructions on page http://docs.moodle.org/23/en/Attendance_module carefully and try again.
By the way, the more details you give in your problem description, the easier it will be for others to offer help.
Thank you for your reply. I also posted the same issue in another discussion thread. Emma posted in the discussion forum with instructions which helped me in installing it and it was done.
Do you have any idea about free pleagiarism checker softwares (e.g. viper) and how to install them.
Hira